Therapeutic Challenges and Future Breakthroughs in Amyotrophic Lateral Sclerosis: From Precision Medicine to Innovative Trial Design

Abstract

Abstract Amyotrophic lateral sclerosis (ALS) is a highly heterogeneous and fatal neurodegenerative disorder, for which clinical management and drug development have long faced formidable challenges. Since the approval of riluzole and edaravone, dozens of promising drug candidates that showed efficacy in preclinical models have failed in Phase III trials, highlighting an urgent need for systematic re-evaluation of the field. This review provides a comprehensive summary of the major limitations of current clinical therapies for ALS. These include the modest survival benefit of riluzole, the narrow eligible population for edaravone, and the complex trajectory of sodium phenylbutyrate-taurursodiol, which received accelerated approval but was subsequently voluntarily withdrawn after its confirmatory Phase III trial failed to meet its primary endpoints. On this basis, we discuss four major challenges that contribute to clinical trial failures: disease heterogeneity, paucity of reliable biomarkers, insufficient translational validity of preclinical models, and inherent flaws in conventional trial designs. Subsequently, we discuss emerging therapeutic strategies, encompassing precision medicine and gene therapy (exemplified by the development of the antisense oligonucleotide tofersen for SOD1-ALS), targeting protein homeostasis, modulation of neuroinflammation, metabolic and energetic support, neuroprotection and regeneration, as well as multi-target combination approaches. Innovative trial designs, including adaptive platform trials (exemplified by the HEALEY ALS Platform Trial), enrichment designs, sequential designs, N-of-1 trials, and virtual clinical trials are fundamentally reshaping the drug development paradigm in ALS. In conclusion, ALS treatment is at a historic turning point from a “one-size-fits-all” approach toward “precisely stratified” medicine. Future success depends on establishing multimodal biomarker panels, implementing genetic testing-guided individualized therapy, developing combination regimens, and integrating patient-reported outcomes with palliative care. Although substantial challenges remain, the clinical success of Tofersen provides evidence that precision therapeutic strategies may gradually transform ALS management toward a more individualized and disease-modifying approach.